[ 5* ] 



5. SALT PETRE. 



The compound of nitrous Acid with Vegetfc 

 ble Alkali. 



5. SALT PETRE.< 



Synonymous Names, 

 r Nitre. 

 Common nitre. 

 Prifmatic nitre. 

 Nitre of potam. 



This is found generally near places inhabited 

 by animals ; it is inflammable, its crystals are lix- 

 fided prifms, terminating in dihedral pyramids, 

 or cut with aflope, and frequently channelled. 



a. When found in water, it may be detected, 

 by heating the water containing it, then adding a 

 little vitriolic acid to it, this unites with the al- 

 kali, forming vitriolated tartar, and detaches the 

 nitrous acid, which being volatile, may be ren- 

 dered fenhble, by holding any thing moiitened 

 with volatile alkali over the furface ; the vipour 

 of the volatile alkali, uniting with the vapour of 

 the nitrous acid, forms a vifible whitifh fmoke, 

 confifting of the nitrous ammoniac in fine duff. 



b. By adding an equal quantity of highly 

 rectified fpirits of wine to this water, it becomes 

 turbid, and this fait is feparated from it, with the 

 appearances as defcribed page 50 d. 



c. A piece of paper moiftened with it, and fuf- 

 fered to dry, will be found to become touch- 

 paper. 



6 COMMON 



